I can't think of anything where the prequels have affected the culture to the extent the OT has (e.g. R2-D2 mailbox, Tom Tom SatNav voices, Trash Compactor book-ends, etc etc).

Yes, the prequels have influenced the Fox media (Simpsons, South Park etc) and generated a ton of short-lived merchandise, but that alone does not qualify as pop culture in my book - just narrow self-serving revenue generation, little "culture".

In the real world there's just no enthusiasm for the prequels amongst everyday people. The opposite was true with the OT and it's really hard to describe to people who weren't even born back then.